In conventional mobile circuit switched networks like GSM (Global System for Mobile communications) the location information of a mobile station is indicated to the network by a BSS (Base Station System). In a mobile IP telephony network, the mobile IP related services may be totally transparent to the underlying access network like GPRS (General Packet Radio Service) so that the access network has no means to provide any location information to the mobile IP telephony core network. Therefore, whenever there is a need for a mobile subscriber's location information in an IP telephony network, the location information (e.g. Cell ID) is not necessarily shown to the application that could have some use for it.